1. Field of the Invention
The present invention relates to a variable beam width lighting device, and in particular, a luminaire assembly which has structure which allows movement of the lamp with respect to the reflector to vary beam width between a spot beam and a flood beam.
2. Problems in the Art
In many lighting applications, it would be advantageous to be able to control the beam width of the lighting device. In some instances, a narrow spot beam would be desirable, whereas in other situations, a diverse flood beam would be most useful. Furthermore, many times it would be desirable to have the ability to alter the beam characteristic produced by the lighting device instantaneously, and easily.
Lighting applications where such beam adjustability would be advantageous includes movie lighting, sports lighting, promotional activities, and other productions. While adjustable beam width lighting would prove useful in many diverse applications, it is particularly useful where large amounts of light are needed thus requiring large fixtures and high powered lamps.
Various methods have been attempted in the past to produce a variable beam luminaire assembly. In some of these attempts, the reflector is movable with respect to the lamp. Others utilize two lamps fixed at different positions with regard to the reflector and which can alternately be used. The problems and impracticalities of these various methods become acute when applied to large, high powered luminaire assemblies.
Many previous methods tried to accomplish variable beam lighting to some extent. However, there still exists a real need for a variable beam width lighting device which produces a maximum amount of light to a target area whether in a spot beam or flood beam mode, or anywhere in between; and at the same time a light device which involves a minimum of structure, expense, weight, and complexity. Furthermore, there is a need for such a device which is easily and efficiently operable, even from a remote location, to adjust the beam width to a desired width anywhere between spot beam and flood beam. It is also desirable to have a device which allows smooth transition between spot beam and flood beam. Previous attempts at producing a variable beam with smooth transitions have not been satisfactory. Some devices utilized reflectors with specular surfaces. However, transition from spot to flood beam was not smooth. Alternating areas of high and low intensity light were produced. The beam pattern consisted of a spotty bright center with alternating concentric bright and dark rings. Other devices, to achieve a more uniform intensity beam pattern, utilized a reflector with a diffuse surface. However, this does not allow enough candlepower or an adequate spot beam to be generated.
It is therefore a primary object of the present invention to provide a variable beam width lighting device which improves over or solves the problems in the art.
Another object of the invention is to provide a variable beam width lighting device which can, according to desire, produce a light beam of high intensity which can be adjusted in width between a spot beam and a flood beam.
Another object of the invention is to provide a variable beam width lighting device which produces a smooth transition between different light beam widths.
A further object of the invention is to provide a variable beam width lighting device which is efficient, economical, durable, and simple in structure and operation.
These and other objects, features, and advantages of the invention will become further apparent with reference to the accompanying specification and claims.